[udesk/spec] Minor function signature modification.

Make the buffer argument of udeskDeleteBuffers const, the
function is not supposed to alter its contents.
[udesk/spec] Add include files makefile.

Add a simple makefile to install the udesk specification
headers into the system.
[udesk/dante] Initial commit for a simple implementation.

Initial commit for the Dante reference implementation of udesk,
this is intended to be a small project implementing the udesk spec,
while keeping a very small set of dependencies.